Morning blood pressure surge is associated independently with orthostatic hypotension in hypertensive patients under treatment.

OBJECTIVE: Morning blood pressure surge (MBPS) and orthostatic hypotension (OH) play a role in the occurrence of cardiovascular events. We aimed to investigate the association between MBPS and OH in hypertensive patients under treatment.

PATIENTS AND METHODS: We prospectively included 297 patients (mean age: 53.8±10.7 years, male/female: 101/196) with essential hypertension. Tilt table testing was performed for the diagnosis of OH. OH was classified into three groups as initial OH (0-15 s), classical OH (15 s to 3 min), and delayed OH (3-30 min). Patients were categorized into two main groups: patient with OH or without OH. We used sleep-through MBPS. The MBPS was calculated as the difference between the average blood pressure (BP) during the 2 h after awakening and the lowest night-time BP.

RESULTS: We detected initial OH in two patients, classic OH in seven patients, delayed OH in 20 patients, and delayed OH with syncope in two patients. MBPS, thiazide diuretic, and α-blocker treatments were found to be associated independently with the occurrence of OH. Every 10 mmHg increase in MBPS was found to increase the rate of development of OH by 29.6%. The cut-off value of MBPS obtained by the receiver operator characteristic curve analysis was 35 mmHg for the prediction of OH occurrence (sensitivity: 58.0%, specificity: 68.0%). The area under the curve was 0.657 (95% confidence interval: 0.553-0.771, P=0.004).

CONCLUSION: OH is a major problem in hypertensive patients. Increased MBPS, which can be detected easily by 24-h ambulatory BP monitor, predicts the occurrence of OH independently.